尝试加载UIImagePicker时出现popoverView错误

Question

我正在尝试创建一个弹出式摄像头视图但是我收到此错误

Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[UIPopoverController _commonPresentPopoverFromRect:inView:permittedArrowDirections:animated:]: Popovers cannot be presented from a view which does not have a window.'

我正在调用我的cameraViewController

- (void) cameraButtonSelected
{
    CameraViewController *cameraViewController = [[CameraViewController alloc] init];
    cameraViewController.view.frame = CGRectMake(100.0, 100.0, 200.0, 150.0);
    [self.view addSubview:cameraViewController.view];
}

这是我试图创建的ViewController viewDidLoad方法

- (void)viewDidLoad
{
    [super viewDidLoad];

    if(self.view.window!=nil)
        [objPopView presentPopoverFromRect:self.view.frame inView:self.view permittedArrowDirections:UIPopoverArrowDirectionAny animated:YES];

    UIImagePickerController *imagePicker = [[UIImagePickerController alloc] init];
    imagePicker.delegate = self;
    imagePicker.sourceType =  UIImagePickerControllerSourceTypeCamera;

    objPopView = [[UIPopoverController alloc] initWithContentViewController:imagePicker];
    [objPopView presentPopoverFromRect:CGRectMake(842, 163, 0, 0)
                                inView:self.view
              permittedArrowDirections:UIPopoverArrowDirectionRight
                              animated:YES];
}

Answer 1

我看到两个问题。

• 你这么做太早了。 viewDidLoad意味着你的观点尚未出现在窗口中。它只是意味着视图存在。等到viewWillAppear:或viewDidAppear:这样做。这是视图现在在界面中的标志。您可能必须使用条件才能在第一次执行此操作。
• 这段代码真的很奇怪：

  if(self.view.window!=nil)
      [objPopView presentPopoverFromRect:self.view.frame inView:self.view
           permittedArrowDirections:UIPopoverArrowDirectionAny animated:YES];

  你还没有定义objPopView，另外如果满足这个条件，你将对弹出窗口进行此演示，然后继续进行另一个弹出窗口的演示。